This project will create a new generation of analytical tools to enable chemical information about the brain to be collected in awake and behaving animals at multiple sites simultaneously. Previous research by the PIs and others has demonstrated that useful chemical information can be collected in vivo utilizing electrochemical sensors, typically single carbon fiber microelectrodes. This proposal will adapt existing multi- sensor platforms for applications in awake and behaving animals. The sensor platforms are based on microfabricated microelectrode arrays (MMEA) of carbon sensors developed by the PIs. These carbon sensors enable high-quality electrochemical information to be collected in complex biological environments. Because these MMEAs are made using microfabrication processes they are expected to have advantages compared to traditional carbon fiber microelectrodes in reproducibility and ease of construction; as well as the flexibility to be expanded to increase the number of sensors or molecules to be detected. In vivo information has been collected using these MMEAs in anesthetized animals. This project will improve the state-of-the-art to enable monitoring dopamine release in the caudate putamen of awake and behaving animals. While this project focuses on the caudate putamen, it is expected that the microfabricated probes will be generally applicable for chemical monitoring in the brain and that the number and types of molecules that can be monitored with this technology will continue to expand. PUBLIC HEALTH RELEVANCE: Understanding the underlying chemical contributions to brain function is a critical issue in solving a variety of health and societal issues including depression, drug addiction, and neurodegenerative disorders. This grant develops the tools needed to monitor chemical signaling in the brain of awake and behaving animals. These tools are a critical need for neuroscience research and this work will aid in enabling other researchers access to required technology and infrastructure to make these types of measurements.